Hi guys. I have been flying MK OctaXL (Octa2 - 1 boom forward), and have now built my own carbon frame. For the new design I specifically designed it so that the "front" would be between 2 booms (octa mode), and not have the front as a single boom (octa2 mode). Some of my reasons are: 1. Possibly better vibration isolation system performance due to more balanced layout? Using the red o-ring vibration system attached between the booms makes a nice "X" layout (where quad booms would be, if front was between 2 booms on the quad). My thoughts are that this would give better performance than the default 22.5 degree offset of the standard cinestar 8 layout. To make this work, I drilled 4 new holes in the "CS 8 Vibration Plate" , so that the gimbal now faces directly between 2 of the vibration isolators (red o-rings). 2. Keep the booms out of the shot? The booms can come into shot during fast forward flight (not very often, but at times). Pointing the camera between 2 booms makes the booms effectively slightly shorter than a single boom in the center. Not much of an advantage, but I think it works out about 9mm less. 3. Faster response and more balanced power distribution? 2 motors working together on "pitch" and 2 motors working together on "roll" flight corrections, one clockwise and one counter clockwise, in my little mind is more balanced. Now that I have given it a lot more thought, Im actually thinking that the above points do not actually have weight at the end of the day, and actually both layouts should perform almost exactly the same, with no measurable difference. The neat "X" layout of the vibration dampers is the only advantage at the end of the day, IMHO, and its hard to prove that even that has any real advantage. It should make roll connection between the multi and the gimbal slightly more firm, but hard to prove or test that. Im interested to hear if any of you have tried both modes (1 boom or 2 booms as front), and if you noticed any differences in flight behaviour, performance, etc.
It would be interesting to compare the Motor currents and BL Temperature data between Octo and Octo2 modes, John. Do you happen to have that data. Specifically, I'm curious to see how the different mixer settings might alter things. Thanks Andy.
Sorry, I have not done a side by side test, as my old frame is totally different to the new frame. Maybe someone with a CS 8 could do the test?
So now I am more than a bit curious. Scope of delivery for an MK Okto XL in the boom department: Riggers 460mm (4x) Riggers 355mm (4x) The kit comes with 12" props, however MK does have a 14" prop offering. We have not tried the 14s on the MK Okto XL yet. Maybe someone else here has and can chime in. I'd be interested in the flight characteristics of a CineStar8 in the "true" MK okto2.mkm file configuration. Again, maybe some of the FF boys have tried it and can chime in before I take 8 CF booms over to the cut-off saw and try and re-invent the wheel. It would have the advantage of a smaller form factor, at the very least. Also, in-flight directional recognition is easier to discern in this configuration...that may be debatable. Now if it would just quit raining we could actually test some of this stuff! Greetings, Adam
My old frame is the MK Octa XL, with 4 short and 4 long alu square 10mm booms. I would imagine this was done to reduce the flex that the long arms have (shorter arms flex less than longer arms). I built a new frame because the flex on the OctaXL was too much for my liking, particularly with the 7D on. Pushing past the limits of what the MK OctaXL was designed for IMHO. Flies great with cx760, or smaller cameras though. Does the 4 short arms and 4 long arms combo work better or worse than 8 long arms? Thats a good question! Would love to hear your results on that.
#2 is one of the reasons I was thinking about switching to an "octo" setup for filming. My other gripe with the "octo2" setup is the Y lighting...I would much prefer having this lit like a full size aircraft. Red lights on the left, green lights on the right, with two white in the rear (all booms lit). I feel this would greatly help me with orientation in low light scenarios. It doesn't seem like anyone has tried this with the C8, but I do enjoy being different. I know this thread is two years old, but is there any update on the pro's and con's between these two mixer setups? Alex
Alex: I think the lighting is matter of personal choice, although I can anticipate that it will not be too long before aviation authorities insist that we use red for the left boom and green for the right. (e.g. red #6, green #3). We'll probably then have to revert to use blue for #1. As to the Octo versus Octo 2, I'm not in a place where I can do a detailed comparison, but, if my memory is correct, that's also a matter of personal choice. Andy.